Liquid fuel injection pumping apparatus

ABSTRACT

A liquid fuel pumping apparatus including an axially movable shuttle, the extent of movement of which is limited by fluid pressure operable piston member having a cylindrical portion which is eccentrically disposed relative to the axis of the bore containing the piston member, the surface of the cylindrical portion defining a stop surface for the shuttle.

United States Patent [191 v Mowbray [451 Jan. 23, 1973 i 1 LIQUID FUELINJECTION PUMPING APPARATUS [75] inventor: Dorian Farrar Mowbray,Burnham,

England [73] Assignee: C. A. V. Limited, Birmingham, En-

gland [22] Filed: Oct. 2, 1970 [21] Appl.No.: 77,687

[30] Foreign Application Priority Data Oct. 3, i969 Great Britain..48,628l69 [52] U.S. Cl ..-..4l7/462 [5 1] Int. Cl ..F04b 19/02 [58]Field of Search 417/462, 245, 212, 485

i561 References Cited UNITED STATES PATENTS Kemp ..'....4l7/2l23,433,!60 3/1969 Kemp ..4l7/245 3,506,381 4/1970 Kemp ..4l7/4853,507,579 4/l970 Kemp r ..4l7/485 3,500,749 3/1970 Kemp et al. ..4l7/485Primary Examiner-William L. Freeh Attorney-Holman & Stern [5 7] ABSTRACTA liquid fuel pumping apparatus including an axially movable shuttle,the extent of movement of which is limited by fluid pressure operablepiston member having a cylindrical portion which is eccentricallydisposed relative to the axis of the bore containing the piston member,the surface of the cylindrical portion defining a stop surface for theshuttle.

3 Claims, 2 Drawing Figures 1 LIQUID FUEL INJECTION PUMPING APPARATUSThis invention relates to liquid fuel pumping apparatus for supplyingfuel to internal combustion engines and of the kind comprising a shuttlemovable in a bore and adjustable stop means positioned at one end of thebore for limiting the excursion of said shuttle.

The object of the invention is to provide such a pumping apparatus in asimple and convenient form.

According to the invention a liquid fuel pumping apparatus of the kindspecified comprises in combination, an axially movable member disposedfor movement along an axis disposed substantially at right angles to theaxis of the bore, a cylindrical portion of said member beingeccentrically disposed relative to the axis of movement of the member,and the cylindrical portion having a contoured stop surface againstwhich the shuttle bears, the arrangement being that axial movement andangular movement of the member or both will vary the permitted excursionof the shuttle in the bore.

ln the accompanying drawings:

F [G 1 is a sectional side elevation of one example of a pumpingapparatus in accordance with the invention, and

FIG. 2 is a part section on the line 2-2 of FIG. 1.

With reference to the drawings there is provided a body part in which ismounted a rotary cylindrical distributor 11. This is arranged to bedriven in timed relationship with the engine with which the apparatus isassociated and at one end is provided with a transverse bore whichaccommodates a pair of plungers 12. The portion of the bore lyingbetween the plungers communicates by way of a longitudinal passage inthe distributor with a radial delivery passage 13 also formed in thedistributor and this is arranged to communicate in turn and as thedistributor rotates, with a plurality of outlet ports 14 formed in thebody part and in communication respectively with injection nozzlesmounted in known manner on the associated compression ignition engine.

The plungers 12 are arranged to be moved inwardly as the distributorrotates, by means of cam followers 40 which co-act with cam surfacesformed on a surrounding annular cam ring 41. The cam ring, followers andplungers constitute an injection pump which partakes of an injectionstroke so that fuel is expelled from the bore containing the plungers 12during the time the delivery passage 13 is in register with an outletport 14.

At a point axially removed from the delivery passage 13 the longitudinalpassage communicates with a plurality of radial inlet passages 15 andthese are arranged to register in turn as the distributor rotates, withan inlet port formed in the body part and in communication with one endof a cylinder 16 containing an axially movable cylindrical shuttle 17.The aforesaid registration of the inlet port and an inlet passage 15takes place during a filling period of the injection pump during thetime when the plungers 12 are allowed to move outwardly and whilst thedelivery passage I3 is out of register with a delivery port 14.

Fuel is supplied to said one end of the cylinder 16 by way of aplurality of longitudinal grooves 18 formed in the periphery of thedistributor and extending from a circumferential groove 19. Theregistration of one of the grooves 18 with a supply passage 20 occursduring an injection stroke of the injection pump so that fuel which isdelivered to the groove 19 from an outlet 21 of a feed pump 22, by wayof a throttle flows to the inner end of the cylinder 16 and causes theshuttle 17 to be moved outwardly. Fuel leaves the other end of thecylinder 16 by way of a passage 23 in the bodypart.

This passage is in communication with a further circumferential groove24 formed in the periphery of the distributor and from this groove 24extend further axial grooves 25 and these during the movement of theshuttle towards the other end of the cylinder, communicate with spillpassages 260. During the filling period of the injection pump one of thegrooves 25 communicates with a feed passage 26 which is in communicationwith the outlet 21 of the feed pump, so that fuel under pressure issupplied to the other end of the cylinder 16 and the shuttle is movedtowards said one end of the cylinder thereby causing the previouslythrottled quantity of fuel contained therein to be delivered to theinjection pump for delivery to the engine during the next injectionstroke. The excursion of the shuttle in the cylinder thereforedetermines the quantity of fuel which will next be delivered to theengine.

In order to control the maximum quantity of fuel which is supplied tothe engine the excursion of the shuttle 17 is limited by a stop. Asshown in the drawing the stop has the form of an axially movablecylindrical member in the form of a piston which is slidably mountedwithin a cylinder 51 the axis of which is at right angles to the axis ofrotation of the distributor. The piston 50 is loaded by a pair of coiledcompression springs 52 and is moved against the action of the springs byfluid under pressure which is supplied to the right hand end of thecylinder 50 through a passage (not shown). The fuel under pressure isobtained from the outlet of the feed pump, the outlet pressure of thefeed pump being controlled in such a manner that it varies in accordancewith the speed at which the apparatus is driven.

The right hand end of the cylinder 51 is closed by a plug housing 53 inwhich is located an angularly adjustable plug 54. At its inner end theplug 54 is provided with a projection 55 of a non-circular section andthis is located within a complementary recess formed in the piston 50.In this manner the piston 50 is allowed to move axially but its angularmovement is prevented. However, by rotating the plug member 54 theangular setting of the piston can be adjusted. Intermediate its ends thepiston is provided with a cylindrical portion 56 which is eccentricallydisposed relative to the axis of the bore 51. Furthermore, the surfaceof the cylindrical portion is contoured and defines a stop surfaceagainst which a projection 57 on the shuttle 17 can bear. Thearrangement is such that for a given setting of the plug 54 thepermitted outward movement of the shuttle l7 will vary inaccordance withthe speed at which the apparatus is driven. However, to enable initialadjustment of the maximum fuel quantity to take place the plug member 54can be moved angularly to adjust the datum position of the stop surface.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

l. A liquid fuel pumping apparatus for supplying fuel to internalcombustion engines and comprising an injection pump including a plungerreciprocable within a cylinder, means for imparting movement to theplunger, an outlet communicating with said cylinder and through whichfuel flows when movement is imparted to said plunger by said means, aninlet communicating with said cylinder and through which fuel flows totill the injection pump, a bore in which fuel is stored prior to flowingthrough said inlet to the injection pump, a shuttle movable in saidbore, an axially movable member disposed for movement along an axisdisposed substantially at right angles to the axis of the bore, acylindrical portion of said member being eccentrically disposed relativeto the axis of movement of the member, and a contoured stop surfaceformed on the cylindrical portion and against which the shuttle bears,the arrangement being that axial movement and angular movement of themember or both will vary the permitted excursion of the shuttle in thebore to control the volume of fuel flowing to the inlet.

2. An apparatus as claimed in claim 1 in which said member constitutes afluid pressure operable piston and there is provided a plug member whichis angularly adjustable from the exterior of the apparatus, and meansconnecting the members which permits relative axial movement but whichprevents relative angular movement.

3. An apparatus as claimed in claim 2 in which the plug member isprovided with a projection of non-circular section and which is engagedwithin a complementary recess in the piston.

1. A liquid fuel pumping apparatus for supplying fuel to internalcombustion engines and comprising an injection pump including a plungerreciprocable within a cylinder, means for imparting movement to theplunger, an outlet communicating with said cylinder and through whichfuel flows when movement is imparted to said plunger by said means, aninlet communicating with said cylinder and through which fuel flows tofill the injection pump, a bore in which fuel is stored prior to flowingthrough said inlet to the injection pump, a shuttle movable in saidbore, an axially movable member disposed for movement along an axisdisposed substantially at right angles to the axis of the bore, acylindrical portion of said member being eccentrically disposed relativeto the axis of movement of the member, and a contoured stop surfaceformed on the cylindrical portion and against which the shuttle bears,the arrangement being that axial movement and angular movement of themember or both will vary the permitted excursion of the shuttle in thebore to control the volume of fuel flowing to the inlet.
 2. An apparatusas claimed in claim 1 in which said member constitutes a fluid pressureoperable piston and there is provided a plug member which is angularlyadjustable from the exterior of the apparatus, and means connecting themembers which permits relative axial movement but which preventsrelative angular movement.
 3. An apparatus as claimed in claim 2 inwhich the plug member is provided with a projection of non-circularsection and which is engaged within a complementary recess in thepiston.